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Tuesday, October 30, 2012

Sometime back in the early 1990s or thereabouts, Dolly Parton was
being interviewed by the famous BBC chat show host, Michael Parkinson. When
asked about what diet she used to keep her figure, she replied: “Honey, if you
want to lose weight, get your head out of the slop bucket”. In other word, just eat less. No truer
words were ever uttered in the vast realm of advice on dieting. This year we
have seen a number of scientific papers published on sugar sweetened beverages,
some designed to boost weight gain and some designed to induce weight loss, all
adding to the belief that sugar sweetened beverages are both the cause and the
cure for modern obesity. A recent paper from the Department of Nutrition at
Harvard will help put things in perspective, but only for those wishing to have
an accurate perspective.

The first [1] of the sugar
papers looked at four groups each given 1-liter of a beverage per day for 6
months. Group 1 receiver a liter of regular sugar sweetened Coke. Group 2 were
given a liter of semi-skimmed milk with an approximate equal calorie level to
the Coke. Groups 3 and 4 respectively received 1 liter of diet Coke or water.
According to the authors, the consumption of the energy-containing beverages
led to a compensation effect with a reduction in the intake of other foods and
no overall change in energy intake. No dietary data are provided in the paper
but 1 liter of regular Coke would have diluted out its equivalent caloric value
from all other foods, leading to a reduction in the intake of the latter by 430
calories per day. This Coke group showed a significant accumulation of fat in
the liver compared to others but we will never know if it was due to the
absurdly high total intake of sugars (about double the normal according to my
calculations) or to a reduction in the intakes of micro-nutrients associated
with 430 less food than normal every day. Coke for example, does not contain, the
B-vitamin riboflavin, but low riboflavin status will lead to increased blood
pressure, and the authors did see a rise in blood pressure with regular
Coke.

So, 1 liter of Coke per day did not lead to weight gain ( for example
a 1.3% gain with Coke and a 0.8% gain with water). However, two studies
reported in the New England Journal of Medicine show that if sugar sweetened
beverages in children are replaced with a calorie free version, then weight
loss does occur [2]. These
studies will be widely cited as evidence that sugary drinks cause obesity. In
fact, these studies simply show that if you do as Dolly Parton says, and simply
eat less, you will lose weight so the weight loss could have been with any
caloric source, not just sugar-sweetened beverages.

Which brings me to the Harvard paper [3].
This study (a subset of a larger dietary intervention) looked at how variation
in the distribution of calories in a weight loss regimen influenced weight
change and also changes in body composition. Four dietary treatments were used
and an energy deficit of 750 kcal per day was the target for each participant.
The diets varied the level of fat, protein and carbohydrate. At 6 months, the
average amount of fat lost was 4.2 kg and the loss of lean tissue was 2.1
kg. About half of this fat loss
was due to loss of fat from the abdominal fat with about a third lost from
subcutaneous fat. Only 0.1 kg of fat was lost from the liver but this
represented a loss of 16% of liver fat. There were no differences in any of
these measures according to the composition of the weight reduction diets,
again, upholding the Dolly Parton rule.

In summary, the first study tells us that if you oblige subjects to
eat a 1-liter bottle of regular Coke every day, you won’t gain weight because
you reduce your intake of other foods keeping energy intake constant. The
second tells us that extracting calories from children’s diets will lead to a
weight loss, in this case using sugar sweetened beverages as the target food.
The third tells us that Dolly Parton was correct. It really doesn’t matter what
the composition of your weight reducing diet is so long as the caloric
restriction operates.

So for what its worth, here are my basic rules about successful
dieting:

1.Never start a diet until you have though
about it long and hard given that the relapse rate of weight loss is so high.

2.Never start a diet until you have built
physical activity into your daily routine. Physical activity will reverse the
negative effects of obesity such as poor glucose management, higher blood
pressure and elevated blood lipids.

3.Don’t diet on your own. Join a weight loss
group and get the benefit of the social network of dieting and maintaining
weight loss.

4.Heed Dolly Parton and just eat less and
eat according to your preferences

Monday, October 22, 2012

During this
summer, I recall reading in the Sunday Times that the environmental NGOs are
beginning to re-think their strategy on GM foods. I see some evidence that this
is the case since I cannot find any mention of the following paper on any of
their websites: Séralini et al (2012)
“Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically
modified maize”[1]. The
publication of this paper has led to the greatest backlash by the scientific
community that I have seen in 4 decades in this business. Essentially, Séralini
published a paper showing that rats exposed to a GM food (maize) and a
herbicide (which is used with the resistant GM crop) developed breast tumors
significantly faster and to a greater extent than controls rats over 104 weeks (2
years). The most significant critic is the European Food Safety Authority
(EFSA), which is the independent body charged with protecting consumer health
in the EU and which is the judge, on the consumers’ behalf, of all scientific
publications on food safety including those on GM technology.

The authors used
Sprague-Dawley rats that will naturally develop tumors over their lifetime
irrespective of any dietary or other treatment and the authors did not discuss
the implications of this natural tendency to tumor development for their study.
They also used 10 rats per treatment, which according to OECD protocols is
adequate for standard 90-day toxicity studies. Monsanto’s submission to EFSA on
the GM maize (NK603) used only 10 rats per treatment, but it was for a 90-day
toxicity study. However, Séralini’s study was over a “lifetime” and the OECD
guidelines recommend the numbers now be increased to 20 per treatment for
chemical toxicity tests but that for carcinogenicity studies, this should be
increased to 50 per treatment. In an article on this topic, Nature contacted
Harlan Laboratories who supplied the rats and were told that for this strain of
rat, only 33% of males and 50% of females live to 2 years. According to the
OECD protocols, if a study is to last 104 weeks, then the survival rate should
be 50% at least and that then 130 rats (half male half female) should be used
per treatment.

The lead author
apparently agrees that more rats per treatment would have boosted his
statistical power but according to Nature[2],
he argues that he did not design the study to find tumors.If at this stage you are confused, then
you’re normal!!!

Further
criticism from EFSA includes the fact that no information is given on the
composition of the rat diets and that no data is given on how much of the
herbicide was consumed through its route, drinking water. No data are given on
lesions that were found which were not tumors or dropout rates and reasons for
dropouts. In addition, the EFSA working group state that the statistical
techniques used were not “commonly-used statistical methods” and that the
authors do not state whether the unusual statistical techniques they used were,
in fact, the a priori choice and if
so, why so? Finally EFSA requested the basic data from the authors to examine
these shortcomings and they were refused access. Trust is hard won but easily
lost.

If all that
wasn’t bad enough, Nature reports on a very sinister dimension to this saga,
which has not received widespread attention. According to their correspondent,
Declan Butler, the author orchestrated a very tight media offensive that
included a film and his new book (Tous Cobayes: OGM, Pesticides, Produits Chimique:
All Guinea Pigs, GMOs, pesticides and chemicals) on the work. A select group of
journalists were invited (not from Nature) to preview the paper and were asked
to sign a confidentiality agreement demanding total secrecy until formal
publication. A breach of the terms of the confidentiality agreement would
require, according to Nature, the following: “A refund of the cost of the study
of several million euros would be considered damages if the premature
disclosure questioned the release of the study”. I’m in the wrong business I
believe!!!!

The Ethics
Committee of one of France’s most august academic bodies Centre National de la
Recherche Scientifique described the PR exercise as “inappropriate”.

Who’d like to be
the first to write a review of his new book on Amazon[3]?
Well although I would, it would be so slanderous that I could not ever afford
the libel fee I’d have to pay.

Sunday, October 7, 2012

(Apologies
for non-publication of some recent blogs but China still poses Internet
challenges)

William Wadd,
born in London in 1776. He was from a medical family and he followed in that
tradition, becoming a Member of the Royal College of Surgeons of England in
1801. After a distinguished career in medicine, he was appointed one of the
Surgeons Extraordinary to King George IV in 1820. Wadd wrote notes on his
favourite topic, obesity and although he always proposed to tidy them up for
into a book, they were in fact published in unedited form in1816. His book
(still available on Amazon) bore the lengthy title: ”Cursory Remarks on Corpulence, Or, Obesity Considered As A Disease:
With a Critical Examination Of Ancient And Modern Opinions, Relative To Its
Causes and Cure.” What is
singularly important about this book is its comments on obesity and its
prevalence, its perceived causes and consequences and on its social context all
at the turn of the 18th century. For those of us interested in
obesity all of 2 plus centuries later it is worthwhile reflecting on some of the
comments of Dr Wadd.

Epidemiology:
Of the general epidemiology of obesity prevailing at the time he writes: ”If the increase of wealth and the
refinement of modern times, have tended to banish plague and pestilence from
our cities, they have probably introduced the whole train of nervous disorders,
and increased frequency of corpulence”.He goes on to argue that: ”It
has been conjectures by some that for one fat person in France or Spain, there
are an hundred in England.” These comments on the widespread prevalence of
obesity 300 years ago is in direct conflict with a key assumption of Robert
Kessler in his popular bestseller “An end of overeating” is that obesity is
more or less a recent phenomenon…. A measure of opulence that surprises one at
first but on reflection should not surprise us at all is the advent of
chimneys. Wadd cheekily ponders the adornment of houses with chimneys but
speculates that there is no associated record “…of the front of a house or the windows being taken away to let out,
to an untimely grave, some unfortunate victim, too ponderous to be brought down
the staircase”!

Genetics:
“The predisposition to corpulency varies in different persons. In some it
exists to such an extent, that a considerable secretion of fat will take place
not withstanding strict attention to the habits of life and undeviating
moderation in the gratification of appetite. Such a predisposition is often
hereditary”. It is interesting to note that 300 years ago there was recognition
that obesity had a genetic dimension, which modern research shows to be of the
order of 75% in terms of heredity but which is still so hard to stomach for the
high priests of health eating.

Social
class and the obesogenic lifestyle: “Yet even such dispositions [hereditary]
seem to require certain exciting causes to bring them to action. Of these, a
free indulgence of the table is principal. For it must be admitted that the
lower orders of society, the poor and the laborious are seldom thus encumbered
and it is only among those who have the means of obtaining the comforts of
life, without labour, that excessive corpulency is met with. You may see an
army of forty thousand foot soldiers without a fat man. And I affirm, that by
plenty, and rest, twenty of the forty shall grow fat.”

Comments
on causes:”The article of drink
requires the utmost of attention. Corpulent persons generally indulge to excess;
if this be allowed every endeavour to reduce them will be in vain”. Boo-hoo
for the boozers! On sugar he wrote: ”Negroes in the West Indies get fat at the
sugar season” and he also commented: “The following case, which occurred in my
knowledge, seems to prove how readily the saccharine particles of vegetables
contribute greatly to increase bulk”. He then goes to describe a case history
of a brewer who got fat, not on the alcohol but on the “sweet wort” from which
it was brewed.

Treatments:
He describes very many treatments from vegetarianism (the most popular), the
consumption of vinegar or soap, salivation, perspiration, exercise or
bandaging. He concludes: ”These are the
principal articles that have been resorted to in the treatment of this disease;
and the person who depends solely on the benefit to be derived from the use of
any of them, will find himself grievously disappointed”.

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"Ever seen a fat fox ~ Human obesity explored"

About Me

I graduated from University College Dublin in 1971 with an Masters in Agricultural Chemistry, took a PhD at Sydney University in 1976 and joined the University of Southampton Medical School as a lecturer in human nutrition in 1977. In 1984 I returned to Ireland to take up a post at the Department of Clinical Medicine Trinity College Dublin and was appointed as professor of human nutrition. In 2006 I left Trinity and moved to University College Dublin as Director of the UCD Institute of Food and Health. I am a former President of the Nutrition Society and I've served on several EU and UN committees on nutrition and Health. I have published over 350+ peer reviewed scientific papers in Public Health Nutrition and Molecular Nutrition and am principal investigator on several national and EU projects (www.ucd.ie/jingo; www.food4me.org). My popular books are "Something to chew on ~ challenging controversies in human nutrition" and "Ever seen a fat fox: human obesity explored"